Browse Prior Art Database

Method for Selecting the Correct Audio an IP Multicast Network

IP.com Disclosure Number: IPCOM000005346D
Original Publication Date: 2001-Aug-23
Included in the Prior Art Database: 2001-Aug-23
Document File: 2 page(s) / 24K

Publishing Venue

Motorola

Related People

Daniel J. McDonald: AUTHOR [+6]

Abstract

A communication system can utilize multicast IP technology for transporting audio to endpoint devices on the network. This idea proposes a method for selecting the appropriate audio stream when multiple streams of audio are present on a particular multicast group

This text was extracted from a WORD97 document.
This is the abbreviated version, containing approximately 53% of the total text.

Method for Selecting the Correct Audio an IP Multicast Network

By

Daniel J. McDonald, John W. Maher, David P. Helm, Brian R. Poe, Tom Senese, Jerry

Drobka

Abstract:

A communication system can utilize multicast IP technology for transporting audio to endpoint devices on the network. This idea proposes a method for selecting the appropriate audio stream when multiple streams of audio are present on a particular multicast group.

Background:

A communication system can utilize multicast IP technology for transporting audio to endpoint devices on the network. When performing group call services, there are cases in which endpoints in the network (i.e. base station, console dispatch positions) can not determine the correct audio stream to receive. In these communication systems, a single multicast group can be used for an entire call and multiple devices can transmit audio on this assigned multicast group.

Problem Description:

In a IP multicast based communication system that performs group call, there are cases in which endpoints in the network (i.e. base station, console) can not determine the correct audio stream to receive. It is possible for multiple devices active in the call (i.e. consoles or base stations) to transmit audio on the assigned multicast group. If this occurs, receiving devices that are monitoring the assigned multicast group, need some mechanism to differentiated and filter out the correct audio stream to be played for the call.

Solution:

There is both control signaling and audio payload present when performing a call on a multicast IP network. The control signaling is used to establish the call and the audio payload is used to carry to audio for the call. Two new fields will be added to both the control signaling and audio payload to synchronize the call control messages with the audio stream. These fields are defined as:

Source URID: This is the Universal Resource Identifier that uniquely identifies a sourcing IP network device in the system

AAID: This is the Audio Association Identifier that uniquely identifies a particular call throughout the IP network.

The purpose of the AAID and source URID is to allow any receiving device on the network to uniquely identify a particular audio stream for a call.

Upon receiving a call request, the system call controller will determine if this is a new call request and if the requesting device can source audio for the new call. If it can, the call controller will obtain a new and unique AAID and assign it to the new call. The call controller will grant the call by assigning the appropriate resources for the call (base stations, transcoders, bandwidth, etc.). The sourcing network device for the call will be identified and the URID associated with this device will be utilized in the call control signaling. The call controller will grant the call by issuing call grant me...